U.S. patent application number 10/351245 was filed with the patent office on 2003-07-17 for ribbed electrodes and methods for their use.
This patent application is currently assigned to SURx, Incorporated. Invention is credited to Carter, Garry L., Dietz, Timothy G., Ingle, Frank W., Laird, Robert J..
Application Number | 20030135249 10/351245 |
Document ID | / |
Family ID | 22100613 |
Filed Date | 2003-07-17 |
United States Patent
Application |
20030135249 |
Kind Code |
A1 |
Laird, Robert J. ; et
al. |
July 17, 2003 |
Ribbed electrodes and methods for their use
Abstract
The invention provides improved devices, methods, and systems
for shrinking of collagenous tissues, particularly for treating
urinary incontinence in a noninvasive manner by directing energy to
a patient's own support tissues. This energy gently heats fascia
and other collagenous support tissues, causing them to contract.
The energy will preferably be applied between a pair of large plate
electrodes having cooled flat electrode surfaces separated by an
insulating rib or film. Such cooled plate electrodes are capable of
directing electrical energy through an intermediate tissue and into
fascia while the cooled electrode surface prevents injury to the
intermediate tissue.
Inventors: |
Laird, Robert J.; (Richmond,
CA) ; Ingle, Frank W.; (Palo Alto, CA) ;
Carter, Garry L.; (Pleasanton, CA) ; Dietz, Timothy
G.; (Fremont, CA) |
Correspondence
Address: |
TOWNSEND AND TOWNSEND AND CREW, LLP
TWO EMBARCADERO CENTER
EIGHTH FLOOR
SAN FRANCISCO
CA
94111-3834
US
|
Assignee: |
SURx, Incorporated
Livermore
CA
|
Family ID: |
22100613 |
Appl. No.: |
10/351245 |
Filed: |
January 23, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10351245 |
Jan 23, 2003 |
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09925501 |
Oct 23, 2000 |
|
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6533780 |
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09925501 |
Oct 23, 2000 |
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09229508 |
Jan 12, 1999 |
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6283987 |
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60071324 |
Jan 14, 1998 |
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Current U.S.
Class: |
607/99 |
Current CPC
Class: |
A61B 18/1815 20130101;
A61B 2018/126 20130101; A61N 7/02 20130101; A61B 2017/00084
20130101; A61B 2018/00023 20130101; A61B 2018/00791 20130101; A61B
2018/1467 20130101; A61B 2018/00517 20130101; A61B 2018/1472
20130101; A61B 2018/1253 20130101; A61B 2018/00523 20130101; A61B
2090/3782 20160201; A61B 2018/0016 20130101; A61B 2018/0022
20130101; A61B 2018/00601 20130101; A61B 2018/00553 20130101; A61B
18/1485 20130101; A61B 2218/002 20130101; A61B 2017/003 20130101;
A61B 2018/1273 20130101; A61B 2018/00654 20130101; A61B 2018/00011
20130101 |
Class at
Publication: |
607/99 |
International
Class: |
A61F 007/00; A61F
007/12 |
Claims
What is claimed is:
1. A probe comprising: a first electrode having a first electrode
surface with a first edge; a second electrode having a second
electrode surface with a second edge adjacent the first edge, the
first and second surfaces aligned to simultaneously engage a tissue
surface; and an insulator disposed between the first and second
electrodes, the insulator extending beyond the edges so as to avoid
edge induced concentration of current flux.
2. A probe as claimed in claim 1, wherein the insulator comprises a
protruding rib.
3. A probe as claimed in claim 1, wherein the insulator comprises a
film.
4. A probe comprising: a first electrode having a first electrode
surface for engaging a tissue surface of a tissue; a second
electrode having a second electrode surface oriented for engaging
the tissue surface simultaneously with the first electrode surface;
a rib between the first electrode and the second electrode, the rib
extending beyond the electrode surfaces so as to protrude into the
tissue.
5. A probe as claimed in claim 4, wherein a surface of the rib is
electrically isolated from the first and second electrodes so that
the rib directs a bipolar current flux between the electrode
surfaces into the tissue beyond the protruding rib.
6. A probe as claimed in claim 5, wherein the rib is adapted to
distend the tissue surface.
7. A probe as claimed in claim 5, wherein the rib is adapted to
incise the tissue surface.
8. A probe as claimed in claim 4, wherein the first and second
electrode surfaces are aligned.
9. A probe as claimed in claim 8, further comprising a cooling
system thermally coupled to the first and second electrodes for
cooling the engaged tissue surface.
10. A bipolar probe comprising: a first electrically and thermally
conductive tube having an electrode surface and a side surface with
an edge therebetween; a second electrically and thermally
conductive tube having an electrode surface and a side surface with
an edge therebetween; and an electrical insulation film disposed
between the side surfaces of the tubes, the film being thermally
conductive and having an exposed cooling surface extending between
the electrode surfaces of the first and second tubes, the cooling
surface being thermally coupled to a cooling fluid.
11. A probe as claimed in claim 10, wherein the film extends to the
edges of the tubes and along a portion of the electrode surface of
at least one of the first and second tubes, the cooling fluid being
disposed in the at least one tube.
12. A probe as claimed in claim 11, wherein the film extends over
the edges of the tubes and along portions of the electrode surfaces
of the first and second tube.
13. A probe as claimed in claim 10 further comprising a thermally
conductive cooling tube disposed between the first and second
tubes, the film being disposed over the cooling tube and the
cooling fluid being disposed in the first and second tubes and the
cooling tube.
14. A probe as claimed in claim 10, wherein the electrode surfaces
have exposed widths in a range from about 3 to about 10 mm, and
wherein the cooling surface of the film has a width in a range from
about 3 to about 10 mm.
15. A probe as claimed in claim 10, wherein the electrode surfaces
and the side surfaces define acute angles at the edges, the film
flexing to act as a living hinge coupling the first and second
tubes.
16. A probe as claimed in claim 10, further comprising a bipolar
electrical connector coupled to the first and second tubes by first
and second electrical conductors, the film electrically isolating
the sides of the tubes.
17. A bipolar probe comprising: at least one cooling fluid path;
cooling fluid flowing within the at least one fluid path; a first
electrode thermally coupled to the cooling fluid within the at
least one fluid path; a second electrode thermally coupled to the
cooling fluid within the at least one fluid path; a cooling surface
extending between the first and second electrodes, the cooling
surface being thermally coupled to the cooling fluid within the at
least one fluid path so as to cool a contiguous tissue surface
engaged by the electrodes and the cooling surface while a bipolar
current between the electrodes heats a target tissue disposed at a
distance from the target surface.
Description
CROSS-REFERENCES TO RELATED APPLICATION
[0001] This application claims the benefit of priority from U.S.
patent application Ser. No. 09/925,501 filed on Oct. 23, 2000;
which is a continuation of U.S. patent application Ser. No.
09/229,508 filed on Jan. 12, 1999 (now allowed), and further claims
the benefit of priority from U.S. Provisional Patent Application
Serial No. 60/071,324 filed on Jan. 14, 1998, the full disclosures
of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to medical devices,
methods, and systems. More specifically, the present invention
provides techniques for selectively heating and shrinking tissues,
particularly for the noninvasive treatment of urinary incontinence
and hernias, for cosmetic surgery, and the like.
[0004] Urinary incontinence arises in both women and men with
varying degrees of severity, and from different causes. In men, the
condition occurs almost exclusively as a result of prostatectomies
which result in mechanical damage to the sphincter. In women, the
condition typically arises after pregnancy where musculoskeletal
damage has occurred as a result of inelastic stretching of the
structures which support the genitourinary tract. Specifically,
pregnancy can result in inelastic stretching of the pelvic floor,
the external sphincter, and most often, to the tissue structures
which support the bladder and bladder neck region. In each of these
cases, urinary leakage typically occurs when a patient's
intra-abdominal pressure increases as a result of stress, e.g.
coughing, sneezing, laughing, exercise, or the like.
[0005] Treatment of urinary incontinence can take a variety of
forms. Most simply, the patient can wear absorptive devices or
clothing, which is often sufficient for minor leakage events.
Alternatively or additionally, patients may undertake exercises
intended to strengthen the muscles in the pelvic region, or may
attempt behavior modification intended to reduce the incidence of
urinary leakage.
[0006] In cases where such noninterventional approaches are
inadequate or unacceptable, the patient may undergo surgery to
correct the problem. A variety of procedures have been developed to
correct urinary incontinence in women. Several of these procedures
are specifically intended to support the bladder neck region. For
example, sutures, straps, or other artificial structures are often
looped around the bladder neck and affixed to the pelvis, the
endopelvic fascia, the ligaments which support the bladder, or the
like. Other procedures involve surgical injections of bulking
agents, inflatable balloons, or other elements to mechanically
support the bladder neck.
[0007] Each of these procedures has associated shortcomings.
Surgical operations which involve suturing of the tissue structures
supporting the urethra or bladder neck region require great skill
and care to achieve the proper level of artificial support. In
other words, it is necessary to occlude or support the tissues
sufficiently to inhibit urinary leakage, but not so much that
intentional voiding is made difficult or impossible. Balloons and
other bulking agents which have been inserted can migrate or be
absorbed by the body. The presence of such inserts can also be a
source of urinary tract infections. Therefore, it would be
desirable to provide an improved therapy for urinary
incontinence.
[0008] A variety of other problems can arise when the support
tissues of the body have excessive length. Excessive length of the
pelvic support tissues (particularly the ligaments and fascia of
the pelvic area) can lead to a variety of ailments including, for
example, cystocele, in which a portion of the bladder protrudes
into the vagina. Excessive length of the tissues supporting the
breast may cause the breasts to sag. Many hernias are the result of
a strained, torn, and/or distended containing tissue, which allows
some other tissue or organ to protrude beyond its contained
position. Cosmetic surgeries are also often performed to decrease
the length of support tissues. For example, abdominoplasty (often
called a "tummy tuck") is often performed to decrease the
circumference of the abdominal wall. The distortion of these
support tissues may be due to strain, advanced age, congenital
predisposition, or the like.
[0009] Unfortunately, many support tissues are difficult to access,
and their tough, fibrous nature can complicate their repair. As a
result, the therapies now used to improve or enhance the support
provided by the ligaments and fascia of the body often involve
quite invasive surgical procedures.
[0010] For these reasons, it would be desirable to provide improved
devices, methods, and systems for treating fascia, tendons, and the
other support tissues of the body. It would be particularly
desirable to provide improved noninvasive or minimally invasive
therapies for these support tissues, especially for the treatment
of urinary incontinence in men and women. It would further be
desirable to provide treatment methods which made use of the
existing support structures of the body, rather than depending on
the specific length of an artificial support structure.
[0011] 2. Description of the Background Art
[0012] U.S. Pat. No. 5,423,811 describes a method for RF ablation
using a cooled electrode. U.S. Pat. Nos. 5,458,596 and 5,569,242
describe methods and an apparatus for controlled contraction of
soft tissue. An RF apparatus for controlled depth ablation of soft
tissue is described in U.S. Pat. No. 5,514,130.
[0013] U.S. Pat. No. 4,679,561 describes an implantable apparatus
for localized heating of tissue, while U.S. Pat. No. 4,765,331
describes an electrosurgical device with a treatment arc of less
than 360 degrees. An impedance and temperature generator control is
described in U.S. Pat. No. 5,496,312. Bipolar surgical devices are
described in U.S. Pat. Nos. 5,282,799, 5,201,732, and 728,883.
SUMMARY OF THE INVENTION
[0014] In a first aspect, the present invention provides a probe
comprising a first electrode having a first electrode surface with
a first edge. A second electrode has a second electrode surface
with a second edge adjacent the first edge. The first and second
surfaces are aligned so as to simultaneously engage a tissue
surface. An insulator is disposed between the first and second
electrode. The insulator extends beyond the edges so as to avoid
edge induced concentration of current flux. The insulator will
typically comprise a protruding rib or a film.
[0015] In a second aspect, the present invention provides a probe
comprising a first electrode having a first electrode surface for
engaging a tissue surface of a tissue. A second electrode has a
second electrode surface which is oriented to engage the tissue
surface simultaneously with the first electrode surface. A rib
between the first and second electrodes extends beyond the
electrode surfaces so as to protrude into the tissue.
[0016] The rib will generally be electrically isolated from the
first and second electrodes, so that the rib can direct a bi-polar
current flux between the electrode surfaces into the tissue beyond
the protruding rib. The rib may be adapted to distend the tissue
surface (for example, by providing a rounded protruded edge, or by
forming the rib from a soft material), or may instead be adapted to
incise the tissue surface (for example, by forming the rib with a
sharp and/or hard protruding edge). Preferably, a cooling system
will be coupled to the first and second electrodes for cooling the
engaged tissue surface.
[0017] The ribbed probe of the present invention is particularly
well adapted for directing current flux through an intermediate
tissue and into a collagenous target tissue so as to heat and
shrink the collagenous tissue. Cooling of the electrode surfaces
can help minimize collateral damage to the intermediate tissue
during this process.
[0018] In another aspect, the invention provides a probe comprising
first and second electrically and thermally conductive tubes. Each
of the tubes has an electrode surface and a side surface with an
edge therebetween. An electrical insulation film is disposed
between the side surfaces of the tubes. The film is thermally
conductive and has an exposed cooling surface extending between the
electrode surfaces of the tubes, and cooling surface being
thermally coupled to a cooling fluid.
[0019] Advantageously, the film can avoid electrical current
concentrations (and localized overheating) at the edges of the
electrode surfaces, while applying cooling contiguously across a
pair of separated bipolar electrodes.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a schematic illustration of a system for heating
and shrinking fascia disposed between adjacent tissue layers by
heating the fascia between a pair of large, cooled, flat electrode
arrays, according to the principles of the present invention.
[0021] FIG. 2 schematically illustrates the even heating provided
by a current flux between the large, cooled, flat electrode
surfaces of the system of FIG. 1.
[0022] FIGS. 2A-2F schematically illustrate structures and methods
for selectively energizing the electrode surface segments of the
large, flat electrode arrays of the system of FIG. 1 to tailor the
current flux throughout a target zone.
[0023] FIGS. 2G and H illustrate a probe structure in which an
insulator is disposed between the electrodes to prevent edge
induced current flux concentration, thereby enhancing the probe's
ability to direct a current flux deep into tissues without inducing
collateral damage at the engaged tissue surface.
[0024] FIGS. 3-3E graphically illustrate a method for heating a
target tissue between cooled electrodes, wherein the electrode
surfaces cool the tissue before, during, and after radiofrequency
energy is applied.
[0025] FIG. 4 is a cut-away view illustrating pelvic support
structures which can be targeted for non-invasive selective
contraction using the methods of the present invention.
[0026] FIGS. 4A-4C illustrate contraction and reinforcing of the
pelvic support tissues of FIG. 4 as a therapies for female urinary
incontinence.
[0027] FIG. 5 is a perspective view of a system for treating female
urinary incontinence by selectively shrinking the endopelvic
fascia, according to the principles of the present invention.
[0028] FIG. 6 is a cross-sectional view illustrating a method for
using the system of FIG. 5 to treat female urinary
incontinence.
[0029] FIG. 7 illustrates an alternative bladder electrode
structure for use in the method of FIG. 6.
[0030] FIGS. 8A and 8B illustrate an alternative vaginal probe
having a balloon deployable electrode for use in the method of FIG.
6.
[0031] FIG. 9 is a cross-sectional view illustrating a structure
and a method for ultrasonically positioning a temperature sensor
within a target tissue.
[0032] FIG. 10 illustrates an alternative system for selectively
shrinking fascia through intermediate tissues, according to the
principles of the present invention.
[0033] FIG. 11 schematically illustrates an alternative method for
selectively shrinking endopelvic fascia using a vaginal probe
having a cooled electrode array.
[0034] FIG. 12 schematically illustrates a cooled bipolar vaginal
probe and a method for its use, the method including insulating a
surface of the endopelvic fascia opposite the probe to limit the
depth of heating.
[0035] FIG. 13 schematically illustrates a method for selectively
shrinking endopelvic fascia by transmitting microwave or ultrasound
energy from a cooled vaginal probe.
[0036] FIG. 14 is a cross-sectional view illustrating a method for
selectively shrinking endopelvic fascia by grasping and folding the
wall of the vagina or colon to facilitate focusing of heating upon
the fascia, and to enhance shrinkage of the fascia by decreasing
tension in the fascia while the fascia is heated, according to the
principles of the present invention.
[0037] FIG. 15 is a schematic illustration of a kit including the
vaginal probe of FIG. 5, together with instructions for its use to
shrink tissues, according to the methods of the present
invention.
[0038] FIG. 16 illustrates an exemplary probe structure having two
bipolar cooled electrode surfaces for heating a target tissue
through an intervening tissue.
[0039] FIG. 17 illustrates an alternative exemplary probe structure
similar to the probe of FIG. 16, having three alternating bipolar
electrodes.
[0040] FIG. 18 is a cross-sectional view through the electrodes of
FIG. 16.
[0041] FIG. 19 is a cross-sectional view through the electrodes of
FIG. 17.
[0042] FIGS. 20A-C illustrate further alternative cooled bipolar
probe structures.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
[0043] The present invention optionally relies on inducing
controlled shrinkage or contraction of a support tissue of the
body, typically being a collagenous tissue such as fascia,
ligament, or the like. For treatment of urinary incontinence, the
tissue structure will be one that is responsible in some manner for
control of urination, or for supporting a such a tissue. Exemplary
tissue structures include the urethral wall, the bladder neck, the
bladder, the urethra, bladder suspension ligaments, the sphincter,
pelvic ligaments, pelvic floor muscles, fascia, and the like.
Treatment of other conditions may be effected by selective
shrinking of a wide variety of other tissues, including (but not
limited to) the diaphragm, the abdominal wall, the breast
supporting ligaments, the fascia and ligaments of the joints, the
collagenous tissues of the skin, and the like. Related devices,
methods, and system are also described in co-pending U.S. patent
application Ser. No. 08/910,370, filed Aug. 13, 1997, the full
disclosure of which is incorporated herein by reference.
[0044] Tissue contraction results from controlled heating of the
tissue by affecting the collagen molecules of the tissue.
Contraction occurs as a result of heat-induced uncoiling and
repositioning of the collagen .beta.-pleated structure. By
maintaining the times and temperatures set forth below, significant
tissue contraction can be achieved without substantial collateral
tissue necrosis.
[0045] The temperature of the target tissue structure will
generally be raised to a value in the range from about 60.degree.
C. to 110.degree. C, often being in the range from about 60.degree.
C. to 80.degree. C., and will generally effect a shrinkage of the
target tissue in at least one dimension of between about 20 and 50
percent. In many embodiments, heating energy will be applied for a
period of from 30 seconds to 5 minutes. These heating times will
vary with separation between the parallel plate electrodes, with a
heat time of about 5 minutes often being appropriate for an
electrode separation of about 4 cm. Shorter heat times may be used
with smaller electrode separation distances.
[0046] The rise in temperature may be quite fast, although there
will often be advantages in heating tissues more slowly, as this
will allow more heat to be removed from tissues which are not
targeted for therapy, thereby minimizing collateral damage.
However, if too little heating energy is absorbed by the tissue,
blood perfusion will transfer the heat away from the targeted
tissue, so that the temperature will not rise sufficiently to
effect therapy. Fortunately, fascia and other support tissues often
have less blood flow than adjacent tissues and organs; this may
help enhance the heating of fascia and minimize necrosis of the
surrounding structures.
[0047] The total amount of energy delivered will depend in part on
which tissue structure is being treated, how much tissue is
disposed between the target tissue and the heating element, and the
specific temperature and time selected for the protocol. The power
delivered will often be in the range from 10W to 100W, usually
being about 20W. The temperature will usually not drop
instantaneously when the heating energy stops, so that the tissue
may remain at or near the therapy temperature for a time from about
10 seconds to about 2 minutes, and will often cool gradually back
to body temperature.
[0048] While the remaining description is generally directed at
devices and methods for treatment of urinary stress incontinence of
a female patient, it will be appreciated that the present invention
will find many other applications for selectively directing
therapeutic heating energy into the tissues of a patient body for
shrinking of tissues, for ablation of tissues and tumors, and the
like.
[0049] FIG. 1 schematically illustrates a system 10 for shrinking a
fascia F disposed between first and second adjacent tissues T1, T2.
System 10 includes a pair of electrodes 12, 14 having large,
substantially planar tissue engaging surfaces. Electrodes 12, 14
are aligned substantially parallel to each other with the fascia
(and adjacent tissues) disposed therebetween.
[0050] The surfaces of electrodes 12, 14 which engage the tissue
are cooled by a cooling system 16. The cooling system will
typically include a conduit through the electrode for the
circulation of a cooling fluid, but may optionally rely on
thermoelectric cooling or the like. The temperature of the
electrode surface may be regulated by varying the temperature or
flow rate of the cooling fluid. Cooling may be provided through the
use of an ice bath, by endothermic chemical reactions, by standard
surgical room refrigeration mechanisms, or the like. Ideally, the
cooling system cools an area which extends beyond the energized
electrode surfaces to prevent any hot spots adjacent the tissue
surface, and to maximize the heat removal from the tissue without
having to resort to freezing the tissue.
[0051] Each of the electrodes is separated into a plurality of
electrode segments. For example, the electrode includes electrode
segments 12a, 12b, 12c, 12d, and 12c, each of which is electrically
isolated from the others. This allows the electrode segments to be
individually energized.
[0052] Electrodes 12, 14 are energized by a radiofrequency (RF)
power source 18. Multiplexers 20 individually energize each
electrode segment, typically varying the power or time each segment
is energized to more nearly uniformly heat fascia F. A controller
22 will typically include a computer program which directs the
application of cooling flow and RF power through electrodes 12, 14,
ideally based at least in part on a temperature signal sensed by a
temperature sensor 24. Temperature sensor 24 may sense the
temperature of the tissue at the tissue/electrode interface, or may
alternatively sense the temperature of the fascia itself.
[0053] The use of large cooled plate electrodes to direct an even
electrical current flux can be understood with reference to the
simplified cross-sectional illustration of FIG. 2. In this example,
RF power is applied uniformly across parallel plate electrodes 12,
14 to produce a current through tissue T. As the electrode surfaces
are substantially planar, and as the electrode surfaces are large
compared to the separation between the electrodes, a current flux
26 is substantially uniform throughout that portion of the tissue
which is disposed between the electrode surfaces. The flow of
electrical current through the electrical resistance of the tissue
causes the temperature of the tissue through which the current
passes to rise. The use of relatively low radiofrequency current,
preferably in the range from 100 kHz to 1 MHz, helps to avoid
collateral damage to nerve and muscle tissues.
[0054] Preliminary work in connection with the present invention
has shown that fascia and other collagenated tissues which are
heated to a temperature range of between about 60.degree. C. and
110.degree. C., and preferably between about 60.degree. C. and
80.degree. C., will contract. In fact, unstressed fascia will
shrink between about 30% and 50% when heated for a very short time,
preferably from between about 0.5 seconds to 5 seconds. Such
heating can easily be provided by conduction of RF currents through
the tissue.
[0055] The uniform current flux provided by the large plate
electrodes of the present invention will produce a substantially
uniform heating of the tissue which passes that current. To
selectively target a central portion of the tissue, in other words,
to selectively heat a target portion of the tissue separated from
electrodes 12, 14, the electrode surfaces are cooled. This cooling
maintains a cooled tissue region 28 adjacent each electrode below a
maximum safe tissue temperature, typically being below about
45.degree. C. Even though heat generation throughout the gap
between the electrodes is uniform, the temperature profile of the
tissue between the electrodes can be controlled by removing heat
through the electrode surfaces during heating.
[0056] Generally, sufficient heating can be provided by a current
of between about 0.2 and 2.0 amps, ideally about 1.0 amp, and a
maximum voltage of between about 30 and 100 volts rms, ideally
being about 60 volts rms. The electrodes will often have a surface
area of between about 5.0 and 200 cm2, and the current density in
the target tissue will often be between about 1 mA/cm2 and 10
mA/cm2. This will provide a maximum power in the range from about
10W to about 100W, often being about 20 watts. Using such low power
settings, if either electrode is lifted away from the engaged
tissue, there will be no arcing. Instead, the current will simply
stop. This highlights the difference between the electrical tissue
heating of the present invention and known electrocautery
techniques.
[0057] The ideal geometry to provide a true one-dimensional
temperature distribution would include large parallel plate
electrodes having relatively minimal spacing therebetween. As
tissues which are easily accessible for such structures are fairly
limited, the present invention can also make use of electrode
geometries which vary somewhat from this ideal, particularly
through the use of array electrodes. In fact, the use of a single
array electrode, in combination with a much larger, uncooled
electrode pad may heat tissues disposed near the array, as will be
described hereinbelow. Nonetheless, uniform heating is generally
enhanced by providing electrode structures having tissue engaging
surfaces which are as flat and/or as parallel as practical.
Preferably, the parallel electrode surfaces will be separated by
between about 1/3 and 1.0 times the width of the electrode surfaces
(or of the smaller surface, if they are different).
[0058] The use of an array electrode having multiple electrode
segments can be understood with reference to FIGS. 2A-2D. FIG. 2A
schematically illustrates the shape of a target zone which is
heated by selectively energizing only electrode segments 12c and
14c of cooled electrodes 12 and 14. Once again, it should be
understood that the temperature of target zone 32 (here illustrated
schematically with isotemperature contour lines 30) is the result
of uniform heating between the energized electrode segments, in
combination with cooling of tissue T by the electrode surfaces. To
expand the heated area laterally between the electrodes, electrode
segments 12a, 12b, 12c . . . , and 14a, 14b, 14c . . . , can be
energized, thereby heating an entire target zone 32 extending
throughout tissue T between the electrodes.
[0059] The use of array electrodes provides still further
flexibility regarding the selective targeting of tissues between
electrodes 12 and 14. As illustrated in FIG. 2C, selectively
energizing a relatively large effective electrode surface by
driving electrodes segments 12a, 12b, 12c, 12d, and 12e results in
a low current flux which is widely disbursed throughout the tissue
T engaged by electrode 12. By driving this same current through a
relatively small effective electrode surface using only a single
electrode surface segment 14c produces an offset target zone 34
which is much closer to electrode 14 than to electrode 12.
[0060] To compensate for electrode structures which are not exactly
parallel, varying amounts of electrical current can be provided to
the electrode segments. For example, a fairly uniform target zone
32 may be heated between angled electrodes by driving more current
through relatively widely spaced electrode segments 12a, 14a, and
driving less current through more tightly spaced electrode segments
12e, 14e, as illustrated in FIG. 2D. It should be understood that
these selective targeting mechanisms may be combined to target
fascia and other tissues which are near one slanted electrode, or
to selectively target only a portion of the tissues disposed
between relatively large electrode arrays.
[0061] An exemplary structure for segmented, cooled electrode 12 is
schematically illustrated in FIGS. 2E and F. Electrode 12 here
comprises three electrode surface segments 12a, 12b, and 12c
separated by insulating spaces 21. A plastic housing 23 defines a
flow path between a cooling inflow port 25 and a cooling outflow
port 27, while heat transfer between the cooling fluid and the
electrode surface is enhanced by a thermally conductive front plate
29. Front plate 29 generally comprises a thermally conductive metal
such as aluminum. Electrode surface segments 12a, 12b, and 12c may
comprise surfaces of separated segments 31 of aluminum foil.
Segments 31 may be electrically isolated by a mylar insulation
sheet 33 disposed between the segments and front plate 29.
[0062] The array electrode structures of the present invention will
generally include a series of conductive surface segments which are
aligned to define a substantially flat electrode surface. The
electrode surface segments are separated by an electrically
insulating material, with the insulation being much smaller in
surface area than the conductive segments. Typically, there will be
between 1 and 8 electrode segments, which are separated by a
distance of between about 0.25 mm and 1.0 mm.
[0063] In some embodiments, the peripheral edges of the electrode
segments may be rounded and/or covered by an insulating material to
prevent concentrations of the electrical potential and injury to
the engaged tissue surfaces.
[0064] It should also be understood that while the electrode arrays
of the present invention are generally herein described with
reference to a linear array geometry, the present invention also
encompasses electrodes which are segmented into two-dimensional
arrays. Where opposed sides of the tissue are accessible for
relatively large array structures, such as along the exposed skin,
or near the major cavities and orifices of the body, the electrode
surfaces will preferably be separated by a gap which is less than a
width (and length) of the electrodes.
[0065] In some embodiments, one electrode structure may be disposed
within a large body cavity such as the rectum or vagina, while the
other is placed in an adjacent cavity, or on the skin so that the
region to be treated is between the electrode surfaces. In other
embodiments, one or both electrodes may be inserted and positioned
laparoscopically. It will often be desirable to clamp the tissue
tightly between the electrodes to minimize the gap therebetween,
and to promote efficient coupling of the electrode to the
tissue.
[0066] Referring now to FIGS. 2G and H, an alternative cooled
electrode structure for use with any of the methods, devices, and
systems described herein makes use of an insulator between
electrodes and/or electrode segments to minimize edge induced
current concentration. By positioning an insulating rib or film
between electrodes, the RF current can be directed over the
insulator without having to resort to widely spaced electrodes or
electrode segments, large radiused edges, and the like.
[0067] In general, when two planar electrodes are disposed
side-by-side on a flat (or large radius) surface for the
application of RF energy, maximum heating will occur at the edges
of the electrodes. This non-uniform heating is caused by the
concentration of electrical potential at these locations. For this
reason, it is often preferable to round the edges of plate
electrodes. To further reduce the current density between
electrodes, the edges of bi-polar electrodes (or differentially
powered electrode segments) will also often be separated by a
greater distance than might otherwise be desirable for applying
uniform therapeutic heating, such as to shrink collagenated
tissue.
[0068] To avoid the concentration of heating at the adjacent edges
of electrodes 35 and 37, an insulating rib 39a is positioned
roughly perpendicular to, and disposed between, the two plate
electrodes. Electrical current very near the surface of an
insulator will generally flow parallel to the insulator surface. In
contrast, current which is very near a conductor will generally
flow perpendicular to the conductor surface. In the absence of rib
39a, the current density is greatest directly between the two
electrodes at their adjacent edges, and will tend to cause a burn
at that location.
[0069] By providing vertical rib 39a between the electrode
surfaces, the current can be directed away from the electrodes and
over the protruding rib. As a result, the rib will tend to induce a
region of approximately parallel current flow beyond the end of the
protruding rib and roughly perpendicular to the electrode surfaces.
Advantageously, rib 39a directs the greatest current density deep
into the tissue, allowing a bi-polar current between the electrodes
to heat and shrink fascia F without inducing a burn at the surface
of intermediate tissue T. In some embodiments, rib 39a may distend
the engaged tissue surface. Alternatively, a sharpened rib may
incise the tissue to direct the heating current flux deeper through
the intermediate tissue and into an inaccessible target tissue.
[0070] In alternative embodiments, the insulator may comprise a
film 39b as illustrated in FIG. 2H. Film 39b is disposed between
electrodes 35, 37, and extends over the adjacent edges of the
electrodes to avoid edge induced concentration of current flux at
this location.
[0071] As can be understood with reference to FIGS. 3-3E, the
tissue will preferably be cooled before and after energizing of the
electrodes. FIG. 3 illustrates three distinct regions of tissue T
disposed between electrodes 12 and 14. Target zone 32 will
typically comprise fascia or some other collagenated tissue, while
the surfaces of the electrodes engage an intermediate tissue 36
disposed on either side of the fascia.
[0072] It will generally be desirable to maintain the temperature
of intermediate tissue 36 below a maximum safe tissue temperature
to prevent injury to this intermediate tissue, the maximum safe
tissue temperature typically being about 45.degree. C. To effect
shrinkage of fascia, target zone 32 will typically be heated to a
temperature above about 60.degree. C.
[0073] There will often be a region of stunned tissue 38 disposed
between the safely cooled intermediate tissue 36 and the target
zone 32. This stunned tissue will typically be heated in the range
from about 45.degree. C. to about 60.degree. C., and may therefore
undergo some limited injury during the treatment process. As a
result, it is generally desirable to minimize the time this tissue
is at an elevated temperature, as well as the amount of stunned
tissue.
[0074] As illustrated in FIG. 3A, prior to application of cooling
or heating energy, the temperature profile of tissue T along an
axis X between electrodes 12 and 14 is substantially uniform at
body temperature. The tissue will preferably be pre-cooled by the
surfaces of electrodes 12, 14, generally using an electrode surface
temperature of at or above 0.degree. C. Pre-cooling will
substantially decrease the temperature of intermediate tissues 36,
and will preferably at least partially decrease the temperature of
stunned tissue 38. At least a portion of the target zone remains at
or near the initial body temperature, as illustrated in FIG. 3B.
Pre-cooling time will often depend on electrode separation and
tissue heat diffusity.
[0075] Once the tissue has been pre-cooled, the RF current is
directed through the tissue between the electrodes to heat the
tissue. A temperature sensor can be placed at the center of target
zone 32 to help determine when the pre-cooling has been applied for
the proper time to initiate RF heating. The current flux applies a
fairly uniform heating throughout the tissue between the
electrodes, and the electrode surfaces are often cooled throughout
the heating process. As target zone 32 has the highest temperature
upon initiation of the heating cycle, and as the target zone is
farthest from the cooled electrodes, a relatively small amount of
heat flows from the target zone into the electrodes, and the target
zone is heated to a significantly higher temperature than
intermediate tissue 36.
[0076] Heat is applied until the target zone is at or above a
treatment temperature, typically resulting in a temperature
distribution such as that illustrated in FIG. 3C. To minimize
collateral damage to the adjacent tissues 36 and stunned tissue 38,
the cooling system continues to circulate cold fluid through the
electrode, and to remove heat from the tissue, after the heating
radiofrequency energy is halted. When substantially the entire
tissue is below the maximum safe tissue temperature (as in FIG.
3D), cooling can be halted, and the tissue can be allowed to return
to standard body temperature, as illustrated in FIG. 3E.
[0077] Optionally, RF current may be driven between the two cooled
plate electrodes using intermittent pulses of excitation. As used
herein, intermittent or pulsed excitation encompasses cyclically
increasing and decreasing delivered power, including cyclical
variations in RMS power provided by amplitude modulation, waveform
shape modulation, pulse width modulation, or the like. Such
intermittent excitation will preferably provide no more than about
25% of the RMS power of the pulses during the intervals between
pulses. Preferably, the electrodes will be energized for between
about 10 and 50% of a total heating session. For example,
electrodes 12 and 14 may be energized for 15 secs. and then turned
off for 15 secs. and then cycled on and off again repeatedly until
the target tissue has been heated sufficiently to effect the
desired shrinkage. Preferably, the electrode surfaces (and the
surrounding probe structure which engages the tissue) will be
cooled throughout the on/off cycles of the heating sessions.
[0078] The therapeutic heating and cooling provided by the
electrodes of the present invention will often be verified and/or
controlled by sensing the temperature of the target tissue and the
adjacent tissue directly. Such temperature sensing may be provided
using a needle containing two temperature sensors: one at the tip
to be positioned at the center of the treatment zone, and the
second along the shaft of the needle so as to be positioned at the
edge of the desired protection zone. In other words, the second
sensor will be placed along the border between the intermediate
tissue and the target tissue, typically somewhere along stunned
tissue 38. The temperature sensors will preferably sense the tissue
temperature during the intervals between pulses to minimize errors
induced by the heating RF current flux in the surrounding tissue.
The temperature sensors may comprise thermistors, thermocouples, or
the like.
[0079] The temperature sensing needle may be affixed to or
advanceable from a probe supporting the electrode adjacent to or
between the electrode segments. Alternatively, two or more needles
may be used. Typically, controller 22 will provide signals to
cooling system 16 and the electrodes so that the electrodes chill
the engaged tissue continually while the RF current is pulsed to
increase the temperature of the treatment zone incrementally,
ideally in a step-wise manner, until it reaches a temperature of
60.degree. C. or more, while at the same time limiting heating of
the intermediate tissue to 45.degree. C. or less per the feedback
from the needles.
[0080] In alternative embodiments, pre-chilling time, the duration
of the heat, the lengths of the heating intervals (and the time
between heating intervals) during intermittent heating, and the
radiofrequency heating current may be controlled without having
direct feedback by using dosimetry. Where the thermal properties of
these tissues are sufficiently predictable, the effect of treatment
can be estimated from previous measurements.
[0081] The pelvic support tissues which generally maintain the
position of the urinary bladder B are illustrated in FIG. 4. Of
particular importance for the method of the present invention,
endopelvic fascia EF defines a hammock-like structure which extends
between the arcus tendineus fascia pelvis ATFP. These latter
structures extend between the anterior and posterior portions of
the pelvic bone, so that the endopelvic fascia EF largely defines
the pelvic floor.
[0082] In women with urinary stress incontinence due to bladder
neck hypermobility, the bladder has typically dropped between about
1.0 cm and 1.5 cm (or more) below its nominal position. This
condition is typically due to weakening of the pelvic support
structures, including the endopelvic fascia, the arcus tendineus
fascia pelvis, and the surrounding ligaments and muscles, often as
the result of bearing children.
[0083] When a woman with urinary stress incontinence sneezes,
coughs, laughs, or exercises, the abdominal pressure often
increases momentarily. Such pressure pulses force the bladder to
descend still further, shortening the urethra UR and momentarily
opening the urinary sphincter.
[0084] As can be most clearly understood with reference to FIGS.
4A-4C, the present invention generally provides a therapy which
applies gentle heating to shrink the length of the support tissues
and return bladder B to its nominal position. Advantageously, the
bladder is still supported by the fascia, muscles, ligaments, and
tendons of the body. Using gentle resistive heating between bipolar
electrodes, the endopelvic fascia EF and arcus tendineus fascia
pelvis ATFP are controllably contracted to shrink them and
re-elevate the bladder toward its original position.
[0085] Referring now to FIG. 4A, bladder B can be seen to have
dropped from its nominal position (shown in phantom by outline 36).
While endopelvic fascia EF still supports bladder B to maintain
continence when the patient is at rest, a momentary pressure pulse
P opens the bladder neck N, resulting in a release through urethra
UR.
[0086] A known treatment for urinary stress incontinence relies on
sutures S to hold bladder neck N closed so as to prevent
inadvertent voiding, as seen in FIG. 4B. Sutures S may be attached
to bone anchors affixed to the pubic bone, ligaments higher in the
pelvic region, or the like. In any case, loose sutures provide
insufficient support of the bladder neck N and fail to overcome
urinary stress incontinence, while overtightening of sutures S may
make normal urination difficult and/or impossible.
[0087] As shown in FIG. 4C, by selectively contracting the natural
pelvic support tissues, bladder B can be elevated from its lowered
position (shown by lowered outline 38). A pressure pulse P is
resisted in part by endopelvic fascia EF, which supports the lower
portion of the bladder and helps maintain the bladder neck in a
closed configuration. In fact, fine tuning of the support provided
by the endopelvic fascia is possible through selective contraction
of the anterior portion of the endopelvic fascia to close the
bladder neck and raise bladder B upward. Alternatively, lateral
repositioning of bladder B to a more forward position may be
affected by selectively contracting the dorsal portion of
endopelvic fascia EF. Hence, the therapy of the present invention
may be tailored to the particular elongation exhibited by a
patient's pelvic support tissues.
[0088] As is more fully explained in co-pending U.S. patent
application Ser. No. 08/910,370, filed Aug. 13, 1997 (Attorney
Docket No. 17761-000120), previously incorporated by reference, a
wide variety of alternative conditions may also be treated using
the methods of the present invention. In particular, selective
shrinkage of fascia may effectively treat cystocele, hiatal, and
inguinal hernias, and may even be used in cosmetic procedures such
as abdominoplasty (through selectively shrinking of the abdominal
wall), to remove wrinkles by shrinking the collagenated skin
tissues, or to lift sagging breasts by shrinking their support
ligaments.
[0089] A system for selectively shrinking the endopelvic fascia is
illustrated in FIG. 5. System 40 includes a vaginal probe 42 and a
bladder probe 44. Vaginal probe 42 has a proximal end 46 and a
distal end 48. Electrode 12 (including segments 12a, 12b, 12c, and
12d) is mounted near the distal end of the probe. Vaginal probe 42
will typically have a diameter of between about 2 and 4 cm, and
will often have a shaft length of between about 6 and 12 cm. An
electrical coupling 50 is coupleable to an RF power supply, and
optionally to an external control processor. Alternatively, a
controller may be integrated into the probe itself. A fluid
coupling 52 provides attachment to a cooling fluid system. Cooling
fluid may be recycled through the probe, so that more than one
fluid couplers may be provided.
[0090] The segments of electrode 12 are quite close to each other,
and preferably define a substantially flat electrode surface 54.
The cooling fluid flows immediately below this surface, the surface
material preferably being both thermally and electrically
conductive. Ideally, surface 54 is as large as the tissue region to
be treated, and a thermocouple or other temperature sensor may be
mounted adjacent the surface for engaging the tissue surface and
measuring the temperature of the engaged tissue.
[0091] Urethral probe 44 includes a balloon 56 supporting a
deployable electrode surface. This allows the use of a larger
electrode surface than could normally be inserted through the
urethra, by expanding the balloon structure within the bladder as
illustrated in FIG. 6. Alternatively, a narrower cylindrical
electrode might be used which engages the surrounding urethra, the
urethral electrode optionally being separated into more than one
segment along the length and/or around the circumference of the
probe shaft. Radiofrequency current will divert from such a tightly
curved surface and heat the nearby tissue. The electrode can again
be chilled to protect the urethral lining from thermal damage.
[0092] As illustrated in FIG. 6, the endopelvic fascia will
preferably be disposed between the electrodes of the urethral probe
44 and vaginal probe 42 when the vaginal probe is levered to the
right or left side of the pelvis by the physician. Balloon 56 of
urethral probe 44 is here illustrated in its expanded
configuration, thereby maximizing a surface area of electrode 14,
and also minimizing its curvature (or, in other words, maximizing
the radius of curvature of the electrode surface). Preferably,
cooled fluid recirculating through balloon 56 will cool electrode
14, so that cooled electrodes 12, 14 will selectively heat the
endopelvic fascia EF without damaging the delicate vaginal mucosa
VM or the bladder wall.
[0093] Urethral probe 44 and vaginal probe 42 may optionally be
coupleable to each other to facilitate aligning the probes on
either side of the target tissue, either mechanically or by some
remote sensing system. For example, one of the probes may include
an ultrasound transducer, thereby facilitating alignment of the
electrode surfaces and identification of the target tissue.
Alternatively, the proximal ends of the probes may attach together
to align the electrodes and/or clamp the target tissue between the
probes.
[0094] Referring now to FIG. 7, a mesh electrode 58 may be unfurled
within the bladder in place of urethral probe 44. Mesh electrode 58
preferably comprises a highly flexible conductive element,
optionally being formed of a shape memory alloy such as
Nitinol.TM.. The bladder may be filled with an electrically
non-conductive fluid such as distilled water during the therapy, so
that little or no RF current would flow into the bladder wall
beyond the contact region between the electrode and the bladder. To
limit heating of tissues which are disposed above the bladder, an
upper portion 58 of the mesh structure may be masked off
electrically from the energized mesh surface of the lower
portion.
[0095] FIGS. 8A and 8B illustrate an optional deployable electrode
support structure for use with vaginal probe 42. Electrode 12 can
be collapsed into a narrow configuration for insertion and
positioning within the vaginal cavity, as illustrated in FIG. 8A.
Once electrode 12 is positioned adjacent to the target tissue,
electrode 12 can be expanded by inflating lateral balloon 60 so
that the deployed electrode assumes a substantially planar
configuration. A cooling fluid may be recirculated through lateral
balloon 60 to cool the electrode 12, and a thermally insulating
layer 62 can help to minimize heat transfer from the adjacent
tissues.
[0096] Referring now to FIG. 9, the tissue shrinking system of the
present invention may also include an ultrasonic transducer 64 for
positioning one or both electrodes relative to fascia F. Transducer
64 will preferably include a transducer material such as PVDF
(polyvinyladine fluoride) or PZT-5A (lead zirconate titanate).
Transducer 64 may be incorporated into the probes of the present
invention, thereby allowing the relative positions and angle
between the electrode surfaces to be measured directly.
Alternatively, transducer 64 may be positioned adjacent to fascia
F, and a mark may be drawn upon the exposed skin (or other tissue
surface) adjacent the fascia for subsequent positioning of a
probe.
[0097] Transducer 64 optionally includes a needle guide 66. for
insertion of a biopsy needle 68 through the view of the transducer
and into the fascia. A thermocouple or other temperature sensing
element may then be deployed in place of the biopsy needle.
[0098] Referring now to FIG. 10, an alternative tissue shrinking
system 70 includes an electrode 12 mounted on a speculum 72.
Speculum 72 may be used to manually position electrode 12 within
the vagina (or another body orifice), while an external applicator
74 is positioned against the skin to clamp the target tissue
between electrode 14 and electrode 12. The speculum and external
applicator 74 may be manually manipulated to clamp the target
tissue between these structures, while electrical leads 76 and
cooling fluid conduits 78 couple the probe and applicator to the
remaining system components.
[0099] As described above regarding FIG. 2C, the use of bipolar
electrodes of differing sizes allows the selective targeting of
tissues. Specifically, heating will be concentrated near the
smaller electrode surface. By using one electrode surface which is
much larger than the other, the current density adjacent the large
electrode will remain so low that little tissue heating is produced
at that site, so that the very large electrode surface need not be
cooled. FIG. 11 schematically illustrates a single probe heating
system 80 which takes advantage of this mechanism to selectively
heat fascia near a single probe.
[0100] In single probe system 80, offset target zone 34 is heated
by RF energy selectively directed through the segments of electrode
12. The vaginal mucosa VM disposed between vaginal probe 42 and
endopelvic fascia EF is protected by cooling the surface of
electrode 12, as described above. Bladder B (and the other tissues
opposite endopelvic fascia EF relative to vaginal probe 42) are
heated significantly less than endopelvic fascia EF due to the
divergence of the current as it travels away from electrode 12 and
towards electrode pad 82, which may optionally be disposed on the
abdomen, back, or thigh. Optionally, cooling water may be
circulated through bladder B to further protect these tissues.
Multiplexer 20 selectively energizes the electrode segments for
differing amounts of time and/or with differing power to help
tailor the temperature profile of offset target zone 34 about
endopelvic fascia EF for selective uniform heating with minimal
collateral damage. Various treatment regimes with alternating
heating and cooling cycles can help to focus the heat therapy on
the desired tissues. Multiplexer 20 may be disposed outside of the
body in a proximal housing, in a separate control unit housing, or
the like. The multiplexer can provide electrode segment drive
control, optionally with switches for each electrode segment.
[0101] Referring now to FIG. 12, a cooled bipolar probe 84 includes
many of the structures and features described above, but here
includes a series of bipolar electrodes 86. Bipolar electrodes 86
will preferably be cooled, and cooling surfaces may also be
disposed between the separated electrodes. As more fully described
in co-pending application Ser. No. 08/910,370, filed Aug. 13, 1997
(Attorney Docket No. 17761-000120), bipolar electrodes 86 may
optionally be formed as parallel cylindrical structures separated
by a predetermined spacing to help direct a bipolar current flux 88
through tissue which lies within a particular treatment distance of
probe 84.
[0102] The depth of penetration of the bipolar energy is controlled
by the spacing and size of the electrode structures. The tissues
distant from the cooled electrodes will be heated to a lesser
extent than the tissues directly engaged by the electrodes, but
will also be cooled to a lesser extent by the cooled electrodes and
other cooling surfaces of bipolar probe 84. The tissues close to
the electrodes will be heated to a greater extent, and will also be
cooled more effectively. Therefore, a controlled regimen of timed
pre-cooling and then heating is used to selectively raise the
temperature of endopelvic fascia EF (or any other target tissue),
while the vaginal mucosa adjacent probe 84 is protected by the
cooled probe. Tissues at depths greater than the endopelvic fascia
will generally be protected by the dissipation of bipolar current
88.
[0103] Since radiofrequency heating generally relies on conduction
of electricity through the tissue, one additional mechanism for
protecting the tissues at depths greater than the target area would
be to inject an insulating fluid 90 into the space surrounding the
vaginal wall on the far side of endopelvic fascia EF. Insulating
fluid 90 may optionally comprise a gas such as CO.sub.2, or may
alternatively comprise a liquid such as isotonic Dextran.TM. in
water. Insulating fluid 90 will electrically insulate the adjacent
organs and prevent heating of tissues that might otherwise be in
contact with the vaginal fascial outer lining. Insulating fluid 90
is here injected using a small needle incorporated into bipolar
probe 84, the needle preferably being 22 ga or smaller.
[0104] Referring now to FIG. 13, microwave probe 94 includes
microwave antennas 96 which direct microwave heating energy 98
through the vaginal mucosa VM and onto endopelvic fascia EF.
Microwave probe 94 will again typically include a cooled probe
surface to minimize damage to vaginal mucosa VM. The microwave may
optionally be produced by a phased array microwave antenna to
decrease heating next to the cold probe relative to the heating of
endopelvic fascia EF, or a more conventional microwave antenna may
be used.
[0105] Microwave power having a frequency of about 2250 MHz is most
often used for heating. However, the use of extremely high
frequency microwaves would permit constructive interference at the
intersection of microwave energy streams by control of the
microwave frequency, phase, and electrode spacing. Such
constructive interference of microwaves may be used to enhance the
heating of the target tissue relative to the heat produced in the
intermediate tissue between microwave probe 94 and endopelvic
fascia EF (in this example). Injection of an electrically
insulating fluid, such as Dextran.TM., may be used to absorb
microwave energy and protect tissues beyond the target zone. In
some embodiments, injection of a liquid contrast medium might be
used to enhance visualization of the treatment region, increasing
the visibility and clarity of the vagina V, bladder B, the other
adjacent organs, and the spaces therebetween. Such a contrast
medium will typically be highly visible under ultrasonic or
fluoroscopic imaging modalities.
[0106] An alternative form of energy which may be used in a probe
schematically similar to that illustrated in FIG. 13 is ultrasonic
heating. A cooled ultrasonic probe could be used to provide heating
of the endopelvic fascia adjacent the vagina, preferably while
protecting the adjacent tissues using a material which reflects
ultrasound. Suitable protection materials include CO.sub.2 or a
liquid/foam emulsion material. High intensity ultrasound is able to
heat tissues at a distance from the probe, and may be focused to
apply the most intense heating at a particular treatment site.
Concentration of ultrasound energy deep in the body may avoid
heating of tissues at the entry site of the focused ultrasound
beam, although gas pockets and bony structures may absorb and/or
reflect the focused ultrasound energy, so that tissues may be
damaged by both localized heating and cavitation. Once again, the
surface of an ultrasound probe will typically be cooled to protect
the tissues which are directly engaged by the probe.
[0107] A cross-section of a grasping bipolar probe 100 is
illustrated in FIG. 14. Grasping probe 100 grips and folds an
anterior portion of the vaginal wall, including both the vaginal
mucosa VM and endopelvic fascia EF, as shown. It should be
understood that the targeted fascia may be separated from the probe
by muscle, vasculature, and the like, as well as by vaginal mucosa
VM. Endopelvic fascia EF is typically about 1 mm thick, while the
grasped, folded vaginal wall will typically be between about 10 mm
to 14 mm thick. The folded endopelvic fascia EF may thus be heated
and contracted between cooled bipolar electrodes 102, as described
above. Depending on the length of the fold, cooled bipolar
electrodes 102 may optionally be formed as wide elongate plates.
Grasping may be accomplished mechanically or by applying a vacuum
to draw the vaginal wall into a cavity 104 of grasping probe 100.
By drawing the endopelvic fascia into close proximity of both
electrodes, a finer focusing of the heating may be accomplished,
thereby minimizing the damage to adjacent tissues. Additionally,
grasping probe 100 may draw the tissue inward to relieve any
tension in the fascia, thereby enhance the shrinkage. As described
above regarding FIG. 12, CO.sub.2 or some other insulating medium
may be used for additional protection of adjacent tissues and
organs.
[0108] A kit 110 includes vaginal probe 42 and instructions 112 for
use of the probe to shrink tissues, the probe and instructions
disposed in packaging 114. The instructions may set forth the
method steps for using probe 42 described hereinabove for
selectively shrinking pelvic support tissues as a therapy for
urinary incontinence, or may alternatively recite any of the other
described methods. Additional elements for system 10 (see FIG. 1)
may also be included in kit 110, or may be packaged separately.
[0109] Instructions 112 will often comprise printed material, and
may be found in whole or in part on packaging 114. Alternatively,
instructions 112 may be in the form of a recording disk or other
computer-readable data, a video tape, a sound recording, or the
like.
[0110] The present invention further encompasses methods for
teaching the above-described methods by demonstrating the methods
of the present invention on patients, animals, physical or computer
models, and the like.
[0111] Exemplary cooled bipolar electrode structures having a
protruding film are illustrated in more detail in FIGS. 16-19. A
two electrode probe 110 is illustrated in a front view in FIG. 16.
Two electrode probe has a probe body 112 supporting a first
electrode 114 and a second electrode 116. An electrically
insulating and thermally conducting film 118 extends along the
electrode surfaces, covering the adjacent edges of the electrodes
so as to prevent localized heating and charring of tissues when the
electrodes are energized in a bipolar manner.
[0112] The structure of electrodes 114, 116 can be seen in more
detail in the cross-section of FIG. 18. The electrodes comprise
electrically and thermally conductive materials, typically being
formed as metal tubes, and ideally comprising stainless steel,
brass, copper, steel, titanium, gold, or the like. Optionally, the
exposed electrode surfaces of the electrode tubes may be coated
with a thin film comprising a biocompatible material such as
silver, or any of the other suitable materials listed above.
Electrodes 114, 116 have electrode surface 120 and side surfaces
122 with an edge 124 therebetween. A cooling fluid 126 is disposed
within the lumen of the electrode tubes, and may flow through the
tubes either in series or in parallel, with the cooling fluid flow
path optionally extending through probe body 112, and/or directly
between the electrode tubes. Typical cooling fluids may comprise
electrically conductive fluids such as chilled, physiological
saline in separate fluid paths for the bipolar electrode pairs, but
will preferably comprise a poor electrical conductor such as water
and/or isotonic Dextran.TM. solution. The cooling fluid will
typically be close to, but often above 0.degree. C.
[0113] Film 118 will preferably be electrically insulating and
thermally conducting so as to provide cooling along the exposed
film surface between first and second electrodes 114, 116. Film 118
may comprise a variety of materials, such as Kapton.TM. tape,
Mylar.TM. tape, a PTFE tape such as Teflon.TM., and anodization.
Film 118 may be applied as a tape, a fluid (such as a paint or an
adhesive), a plating, or the like, and will generally have
sufficient thickness to act as an electrical insulator and a
thermal conductor. Further alternative insulation film materials
may comprise polyimide, spray-on ceramics, electroplated
insulation, photoimageable polymers, epoxy, and urethanes. In the
exemplary embodiment, the exposed electrode surfaces 120 have a
width in a range from about 3 mm to 10 mm, while the exposed
cooling surface of film 118 disposed between the electrodes also
has a width in a range from about 3 mm to about 10 mm. The
electrode need not be limited to a one or two dimensional array. In
fact, electrode widths and separation may be easily varied along
the axes of the tubes by applying film 118 over a curving area.
[0114] It should be noted that a wide variety of alternative
electrode configurations might be used within the scope of the
present invention. For example, a three electrode probe 130
includes three tubular electrodes 132, 134, 136 mounted in a
plastic probe body 112, with electrodes and film structures
substantially similar to those of FIGS. 16 and 18. It should be
understood that electrode surfaces 120 need not be completely
planer. For example, the exposed electrode surfaces may comprise
portions of a large diameter cylinder as illustrated in co-pending
PCT Application No. PCT/US98/16754, filed on Oct. 7, 1998, the full
disclosure of which is incorporated herein by reference, or may
comprise portions of a sphere. When more than two electrodes are
provided, they may be energized either simultaneously or
sequentially as bipolar pairs. Once again, a wide variety of
electrode geometries and treatment cycles might be used.
[0115] Still further related cooled probe structures are
illustrated in FIGS. 20A-C. In the embodiment of FIG. 20A, film 118
isolates cooling fluid path tubes 140 electrically, and allows
contiguous cooling across separated bipolar electrodes. This and
other probe structures having three or more electrodes will often
be multiplexed by driving bipolar current between, for example,
electrodes 132 and 134, and then between electrodes 134 and 136.
Cooling tubes 140 are electrically insulated, and can be allowed to
float with respect to electrodes 132, 134, and 136.
[0116] Several factors will alter the heating depth profile for the
bipolar probes of the present invention. First, the width of the
insulation provided by film 118 between the exposed electrodes is
related to the maximum treatment depth. Second, both the width of
the active exposed electrodes and the width of the electrically
insulated separation distance between the electrodes determine the
maximum depth of the intervening tissue which can be thermally
cooled and effectively protected while treating the target tissue.
Third, reducing the separation gap between electrodes will
eventually result in localized hot spots at the surface of the
inside edges of the powered electrodes. The minimum interelectrode
separation can be decreased by multiplexing or alternating the
bipolar power between three or more electrodes as described above.
An electrically insulating film extends to, and preferably over and
beyond the electrode edge, and/or a protruding insulating rib may
also reduce localized hot spots.
[0117] Still further alternative electrode tube/film structures are
illustrated in FIGS. 20B and C. The embodiment of FIG. 20C includes
electrode tubes which define acute angles between the electrode and
side surfaces. Film 118 here acts as a living hinge between the
electrodes, allowing the probe to conform to a curving tissue
surface such as a lumenal wall. The acute tube angles increase the
range of flexibility of the probe, and similar probes may be used
having cooling tubes between active electrodes, a combination of
different electrode tube shapes, or the like.
[0118] While the exemplary embodiments have been described in some
detail, by way of example and for clarity of understanding, a
variety of modifications, adaptations, and changes will be obvious
to those who skill in the art. Therefore, the scope of the present
invention is limited solely by the appended claims.
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